I brewed at 195F in order to exacerbate temperature errors. I put a drop in the Brix meter well and recorded readings every half-minute. Note that the readings were flat (Brix = 3.3) from one half minute to 3.5 minutes.

After 3.5 minutes I'm sure that the sample had cooled to room temperature, but the Brix reading still began to increase -- presumably due to evaporation.

As I posted earlier, I take the first two repeats as the reading. In this case 3.3.

If there was evaporation after the sample cooled surely there was evaporation when it was hot. I'm not sure what's going on, but given the precision of your instrument your data fit a linear increase reasonably well. Look at the attached graph. The error bars denote the precision of your refractometer.

If the increase is due to evaporation it is at the rate of ~1% loss of solution per minute. Your PAL-1 can't resolve that which is why it takes several minutes for the reading to change. I have done evaporation tests before as I was concerned about errors when weighing small liquid coffee samples. I came to the conclusion that at room temperature the evaporation rate for my circumstance was insignificant but it was a source of error if the coffee was hot. So I cool the samples in closed containers.

Why don't you try doing it the way that VST recommends for their refractometers? They suggest putting several milliliters into a room temperature shot glass to quickly cool the liquid, waiting 1 minute, transfering the fraction of a ml needed to fill the sample well, and then waiting another 30 seconds. See if it makes any difference.

Why don't you try doing it the way that VST recommends for their refractometers? They suggest putting several milliliters into a room temperature shot glass to quickly cool the liquid, waiting 1 minute, transfering the fraction of a ml needed to fill the sample well, and then waiting another 30 seconds. See if it makes any difference.

I've been moaning that my basic Cuisinart conical burr grinder doesn't go as fine as I used to get by overgrinding with my old whirly, but today I did an experiment: using my Kaffeologie screen with an AP paper filter added. Here's what got caught by the paper after the screen.

Symbols: = New Posts since your last visit = No New Posts since last visit = Newest post

Forum Rules:No profanity, illegal acts or personal attacks will be tolerated in these discussion boards.No commercial posting of any nature will be tolerated; only private sales by private individuals, in the "Buy and Sell" forum.No SEO style postings will be tolerated. SEO related posts will result in immediate ban from CoffeeGeek.No cross posting allowed - do not post your topic to more than one forum, nor repost a topic to the same forum.Who Can Read The Forum? Anyone can read posts in these discussion boards.Who Can Post New Topics? Any registered CoffeeGeek member can post new topics.Who Can Post Replies? Any registered CoffeeGeek member can post replies.Can Photos be posted? Anyone can post photos in their new topics or replies.Who can change or delete posts? Any CoffeeGeek member can edit their own posts. Only moderators can delete posts.Probationary Period: If you are a new signup for CoffeeGeek, you cannot promote, endorse, criticise or otherwise post an unsolicited endorsement for any company, product or service in your first five postings.